An experimental study on the effect of addition of reformed gas components by steam methane reforming on combustion and ignition characteristics of a methane-fueled spark-ignition gas engine

Engine experiments were conducted to investigate the effects of reformed gas components from steam methane reforming on combustion and ignition (knocking) characteristics of a spark-ignition gas engine fueled with CH 4 . First, the effects of H 2 or CO 2 addition to CH 4 were solely investigated. Next, experiments were conducted using a simulated reformed gas with a 4:1 volumetric ratio of H 2 and CO 2 to clarify the effect of the addition of reformed gas produced by steam methane reforming to CH 4 on the MBT spark timing, brake thermal efficiency, and the knocking limit spark timing. The result showed that the MBT spark timing tended to retard while the peak of the brake thermal efficiency improved. The knocking limit spark timing retarded, and the operable range of spark timing from the knocking limit to the retardation limit (exhaust gas temperature limit) was shortened.